MALFUNCTION OF IMPLANTABLE CARDIOVERTER-DEFIBRILLATORS PLACED BY A NONTHORACOTOMY APPROACH - FREQUENCY OF MALFUNCTION AND VALUE OF CHEST RADIOGRAPHY IN DETERMINING CAUSE

OBJECTIVE. The purpose of this study was to determine the frequency of system malfunction in patients with nonthoracotomy implantable cardio verter defibrillators and to assess the role of chest radiography in d etecting and determining the cause of malfunction. MATERIALS AND METHO DS. The study population consisted of 300 consecutive patients in whom implantable cardioverter defibrillators were implanted using an initi al nonthoracotomy approach between September 1990 and October 1994. Tr ansvenous electrodes were placed via the subclavian or cephalic vein u nder local anesthetic. Intraoperative testing, pulse generator implant ation, and, if necessary, subcutaneous patch or extrapericardial patch placement via thoracotomy were done in the operating room under gener al anesthetic, follow-up consisted of routine device interrogation eve ry 2-3 months and annual chest radiography. Chest radiographs were obt ained more often if patients were symptomatic or if results of device interrogation were abnormal. RESULTS. Patients were followed up for a mean +/- SD of 19 +/- 14 months following implantation. Implantable ca rdioverter-defibrillator malfunction occurred in 17 patients (6%) duri ng the follow-up period. Of these, 12 (71%) had component abnormalitie s on chest radiographs. Patients with radiographically apparent implan table cardioverter-defibrillator abnormalities presented in two discre te ti me periods after device implantation, early (mean, 35 +/- 14 day s) and late (mean, 18 +/- 5 months). CONCLUSION. Malfunction of nontho racotomy implantable cardioverter-defibrillator systems develops infre quently after device implantation. In most cases, the cause can be ide ntified on chest radiographs.